INFORMATION ABOUT ELECTRIC BARRIER AT MENASHA LOCK
Overview of the proposed electric barrier at the Menasha lock
Our goal is to reopen the Menasha Lock, but not without a solution that prevents the invasive round goby from entering the waters of Lake Winnebago. To that end, we have been working with a firm to study the effects of an electronic barrier and water velocity on deterring the fish from entering the lock channel.
Study results show that an electronic barrier combined with increased water velocity deters adult round gobies from entering the lock channel. The current plan calls for building an electric array near the bottom of the Menasha lock channel that would pulse and push the gobies away or immobilize them. Changes in water velocity in the lock channel would be used to flush the lock and further push the gobies away.
The Wisconsin DNR had previously requested the study also be conducted on larval and juvenile round goby. That phase of the study is scheduled for later this year after egg and larvae collection is completed in summer.
If the study results support the efficacy of the electronic barrier, other testing and approvals would need to take place before construction. Please understand this is a very complicated project requiring approvals from multiple parties and extensive engineering/construction planning, so it is impossible to predict a completion date.
Activity as of October 2019
The Authority completed a plan that was submitted to the DNR for review and comment–primary portions of the documents are available for public review at the links below. The DNR responded with questions about information gaps in the proposal and the Fox River Navigational System Authority (FRNSA) board of directors sought out proposals for further study. The board accepted a proposal from Kleinschmidt, an environmental engineering firm, that calls for conducting a suite of studies to provide more complete information to the DNR. This series of studies would provide the following information:
- Comprehensive information about the round goby’s ability to swim against water velocity at all stages of the fish’s life;
- How an electrical field will affect a round goby at all stages of the fish’s life.
Four of the studies would be conducted in a laboratory, the fifth study is optional and would be conducted in one of the closed locks. If all five studies are conducted, the cost would be about $165,000, paid from FRNSA’s capital budget.
This will be the first such scientific study on the behavior of the round goby from larval to adult stages. Consultants are confident the studies will answer all questions raised by the DNR and provide definitive information on the fish’s response to electric currents and water velocity.
The board voted to conduct two of the studies, then get more definitive response from the DNR to determine if the studies will indeed fill the information gaps in the original proposal before more funds are approved. Results from the studies are expected by spring of 2020.
Closing the Menasha lock, the background
The Menasha lock was closed in 2015 due to the discovery of the round goby, an invasive fish species populating the Great Lakes. In order to keep these fish from reaching the Lake Winnebago system, the DNR requested the lock closure, and the Fox River Navigational Authority (FRNSA) complied.
Over the years we have worked with fish researchers, engineers, and an independent fisheries management firm to review the most recent scientific research on invasive species barriers and solutions that have worked for other communities in the Great Lakes region. We have invested about $200,000 to research the behaviors of the round goby and design concepts to do three things:
- Prevent the spread of the round goby into the Lake Winnebago watershed,
- Return the Menasha lock to operation,
- Build a system that can be adapted to prevent the spread of any future invasive species.
Working with experts in aquatic ecosystem management, we designed a plan using a system of an electric deterrent barrier and water flow regulation at the Menasha lock to stop the spread of the round goby. This system has been in concept design, review, and modification for several months and represents a proven technology in combatting invasive species.
The concept is 60% designed and involves building a concrete,, U-shaped channel adjacent to and downstream from the Menasha lock. Electrodes would be recessed in the bottom of the channel. This type of a barrier will allow boat traffic to pass through the channel while halting the passage of fish. The barrier delivers a pulsing DC current to fish entering the channel, causing them to turn around and not enter the lock; it also uses a water velocity process to prevent the round goby from moving into the lock channel. The DC current in the water is not dangerous to humans.
Artist’s rendering of the proposed electric barrier at the Menasha lock
On the east side of the lock we propose installing a kayak launch and cleaning station, a floating dock, a new walkway/portage path, concrete crane pads for lock gate maintenance, and a new building with restroom facilities. On the west side of the lock we propose building a second floating dock and walkway. Modifications will be made to the existing lock tender shack to house the backup equipment needed for the electric barrier.
The Authority completed a plan that was submitted to the DNR for review and comment. The primary portions of the documents are available for public review.
A report on the design of the electric barrier is at this link
A report showing the design of the electric barrier at 60% completion is at this link
A report of construction materials specifications is at this link
An operating manual for the system is at this link.
The plan and supporting studies and documentation was originally presented to the DNR in October of 2018. Copies of that report may be found at this link: Part 1, Part 2. At that time, the DNR had several questions posed to researchers and fish management experts. FRNSA commissioned further research on these topics that include:
A comprehensive review of the round goby available at this link
A review of the behavior of the electric field used in the barrier available at this link
A report on electrical conductivity in varying water conditions available at this link
A comprehensive report on the electric barriers currently in operation available at this link
According to an Economic Impact Study completed in 2017, a fully functioning lock system, including the visitors’ center proposed for Appleton, has a 10-year potential economic impact of:
- $290 million in additional total output accumulated over 10 years
- $176 million in additional labor income accumulated over 10 years
- 6,339 additional jobs accumulated over 10 years
- $99 million in additional business investment accumulated over 10 years
If you have questions about the barrier or any plans, please use our contact form.